Rathcroghan and Carnfree (Celtic Royal Sites in Roscommon), by Prof. Michael Herity. This guide is based on a survey of the antiquities in an area of 100 square kilometres around Cruachain and Carnfree begun before 1980.

The results of the survey have been published in four articles in the Journal of the Royal Society of Antiquaries of Ireland (1983, 1984, 1987, 1988).